Test ID: MEVP
Methemoglobinemia Evaluation
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosis of methemoglobinemia and sulfhemoglobinemia
Differentiation of methemoglobinemia and sulfhemoglobinemia from other causes of cyanosis (eg, congenital heart disease)
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MEV | Methemoglobinemia Interpretation | No | Yes |
| A2F | Hemoglobin A2 and F | Yes | Yes |
| HBEL | Hemoglobin Electrophoresis, B | No | Yes |
| METH | Methemoglobin, B | Yes, (order MET) | Yes |
| SULF | Sulfhemoglobin, B | Yes, (order MET) | Yes |
| METR | Methemoglobin Reductase, B | Yes | Yes |
Reflex Tests Lists test(s) that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial test(s)
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| HPFH | Hemoglobin F, Red Cell Distrib, B | Yes | No |
| UNHB | Hemoglobin, Unstable, B | Yes | No |
| SDEX | Hemoglobin S, Scrn, B | Yes | No |
| IEF | IEF Confirms | No | No |
| HGBMO | HGB Electrophoresis, Molecular | No | No |
| MASS | Hb Variant by Mass Spec, B | No | No |
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
This is a consultative evaluation in which the case will be evaluated at Mayo Medical Laboratories, the appropriate tests performed at an additional charge, and the results interpreted.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
MEV/586: Consultative Interpretation
A2F/83341: Cation Exchange/High-Performance Liquid Chromatography (HPLC)
HBEL/81428: Capillary Electrophoresis
METH/80200, SULF/8272: Spectrophotometry (SP)
METR/9322: Kinetic Spectrophotometry (KS)
SDEX/9180: Hemoglobin S Solubility
UNHB/9095: Isopropanol Stability
HPFH/8270: Flow Cytometry
MASS/60286: Mass Spectrometry (MS)
IEF/81644: Electrophoresis
HGBMO/29374: Polymerase Chain Reaction (PCR) Analysis/Multiplex Ligation-Dependent Probe Amplification (MLPA), Polymerase Chain Reaction (PCR)/DNA Sequencing
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Hemoglobin Spectral Absorbance
Methemoglobin Evaluation
Specimen Type Describes the specimen type needed for testing
Whole Blood EDTA
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen must arrive within 72 hours of draw.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 2 Full 5-mL tubes
Collection Instructions: Do not transfer blood to other containers.
Additional Information:
1. Patient's age and sex are required.
2. Include recent transfusion information.
Forms:
1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
2. Thalassemia/Hemoglobinopathy Information Sheet (Supply T358) is available in Special Instructions
3. If not ordering electronically, please submit a Hematopathology/Molecular Oncology Request Form (Supply T241) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Refrigerated | 72 hours |
| Whole Blood EDTA | Refrigerated | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Methemoglobin:
Methemoglobinemia, with or without sulfhemoglobinemia, is most commonly encountered as a result of administration of such medications as phenacetin, phenazopyridine, sulfonamides, local anesthetics, dapsone, or following ingestion of nitrites or nitrates.
Congenital methemoglobinemias are rare. They are due either to:
-A deficiency of methemoglobin reductase (also called cytochrome B5 reductase or diaphorase) in erythrocytes, an autosomal recessive disorder
-One of several intrinsic structural disorders of hemoglobin, called methemoglobin-M, all of which are inherited in the autosomal dominant mode
Sulfhemoglobin:
Sulfhemoglobinemia often accompanies methemoglobinemia. Sulfhemoglobinemia can be due to exposure to trinitrotoluene and/or zinc ethylene bisdithiocarbamate (a fungicide). The formation of sulfhemoglobin cannot be reversed and there is no therapy for sulfhemoglobinemia. Because patients with sulfhemoglobinemia also often have methemoglobinemia, therapy is directed at reversing the methemoglobinemia present.
Symptoms of both methemoglobinemia and sulfhemoglobinemia are caused by anoxia and are characterized by cyanosis.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Definitive results and an interpretive report will be provided.
Interpretation Provides information to assist in interpretation of the test results
In congenital methemoglobinemia, the methemoglobin concentration in blood is about 15% to 20% of total hemoglobin. Such patients are mildly cyanotic and asymptomatic.
In acquired (toxic) methemoglobinemia, the concentration may be much higher. Symptoms may be severe when methemoglobin is >40% of hemoglobin. Very high concentrations may be fatal.
This is a consultative evaluation in which the history and previous laboratory values are reviewed by a hematologist who is an expert on these disorders. Appropriate tests are performed and an interpretive report is issued.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Sulfhemoglobin is exceedingly stable and does not change in stored or shipped specimens.
Methemoglobin is unstable and can degrade at a rate of about 40% per 24 hours.
A normal methemoglobin value obtained with stored or shipped specimens does not exclude prior methemoglobinemia of minimal degree. However, significant methemoglobinemia will still be demonstrable.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Beutler E: Methemoglobinemia and sulfhemoglobinemia. In Hematology. Fifth edition. Edited by E Beutler, MA Lichtman, BS Caller, TJ Kipps. New York, McGraw-Hill Book Company, 1995, pp 654-663
Method Description Describes how the test is performed and provides a method-specific reference
Hemoglobin A2 and F:
Hemolysate of whole blood is injected into an analysis stream passing through a cartridge containing diethylaminoethyl-resin using HPLC. A pre-programmed gradient controls the elution buffer mixture that also passes through the analytical cartridge. The ionic strength of the elution buffer is raised by increasing the percentage of a second buffer. As the ionic strength of the buffer increases the more strongly retained hemoglobins elute from the cartridge. Absorbance changes are detected by a dual-wavelength filter photometer. Changes in absorbances are displayed as a chromatogram of absorbances versus time.(Huismann TH, Scroeder WA, Brodie AN, et al: Microchromotography of hemoglobins. III. A simplified procedure for the determination of hemoglobin A2. J Lab Clin Med 1975;86:700-702; Ou CN, Buffone GJ, Reimer GL, Alpert AJ: High-performance liquid chromatography of human hemoglobins on a new cation exchanger. J Chromatogr 1983;266:197-205)
Methemoglobin:
The normal absorption spectrum of oxyhemoglobin has very little optical density above 600 nm. The absorption spectrum of methemoglobin exhibits a small, characteristic peak at 630 nm. This peak is abolished as methemoglobin is converted to cyanmethemoglobin upon addition of potassium cyanide, and the drop in optical density is proportional to methemoglobin concentration.(Evelyn KA, Malloy HT: Microdetermination of oxyhemoglobin, methemoglobin, and sulfhemoglobin in a single sample of blood. J Biol Chem 1938;126:655-662; Fairbanks VF, Klee GG: Biochemical aspects of hematology. In Teitz Textbook of Clinical Chemistry. Edited by CA Burtis, ER Ashwood, WB Saunders Company, 1999, pp 1676-1678)
Sulfhemoglobin:
The normal absorption spectrum of oxyhemoglobin has very little optical density above 600 nm. However, if certain poorly defined hemoglobin denaturation products are present in a hemolysate, there is a broad elevation of the absorption curve in the range of 600 to 620 nm. This "sulfhemoglobin" plateau is not affected by treatment with cyanide. Sulfhemoglobin is not available, nor can it be prepared, in a pure form for preparation of a sulfhemoglobin standard. In calculating sulfhemoglobin concentration, the factor for sulfhemoglobin quantitation is based on studies of Carrico, et al (1978).(Evelyn KA, Malloy HT: Microdetermination of oxyhemoglobin, methemoglobin, and sulfhemoglobin in a single sample of blood. J Biol Chem 1938;126:655-662; Carrico RJ, Peisach J, Alben JO: The preparation and some physical properties of sulfhemoglobin. J Analyt Biochem 1978;253:2386-2391; Fairbanks VF, Klee GG: Biochemical aspects of hematology. In Teitz Textbook of Clinical Chemistry. Edited by CA Burtis, ER Ashwood, WB Saunders Company, 1999, pp 1676-1678)
Methemoglobin Reductase:
Methemoglobin reductase (cytochrome B5 reductase) catalyzes the NADH-linked reduction of several substrates, including ferricyanide. The activity at 30 degrees C is followed spectrophotometrically by measuring the oxidation of NADH at 340 nm.(Fairbank VF, Klee GG: Biochemical aspects of hematology. In Tietz Textbook of Clinical Chemistry. Third edition. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Company, 1999, pp 1647-1648)
Hemoglobin Electrophoresis:
The CAPILLARYS System is an automated system that uses capillary electrophoresis to separate charged molecules by their electrophoretic mobility in an alkaline buffer. Separation occurs according to the electrolyte pH and electro-osmotic flow. A sample dilution with hemolysing solution is injected by aspiration. A high voltage protein separation occurs and direct detection of the hemoglobin protein fractions is at 415 nm which is specific to hemoglobins. The resulting electrophoregrams peaks are evaluated for pattern abnormalities and are quantified as a percentage of the total hemoglobin present. Examples of position of commonly found hemoglobin fractions are, from cathode to anode: Hb A2', C, A2/O-Arab, E, S, D, G-Philadelphia, F, A, Hope, Bart, J, N-Baltimore, and H.(Louahabi A, Philippe M, Lali S, et al: Evaluation of a new Sebia kit for analysis of hemoglobin fractions and variants on the Capillarys system. Clin Chem Lab Med 2006;44[3]:340-345)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; Varies
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
Methemoglobinemia Evaluation
82657-Methemoglobin reductase
83020-Hemoglobin electrophoresis
83021-Hemoglobin A2 and F
83050-Methemoglobin, quantitative
83060-Sulfhemoglobin, quantitative
IEF Confirms
82664-Isoelectric focusing (if appropriate)
Hemoglobin, Unstable, Blood
83068 (if appropriate)
Hemoglobin Variant by Mass Spectrometry (MS), Blood
83789 (if appropriate)
Hemoglobin Electrophoresis, Molecular
81257 x 2-HBA1/HBA2 (alpha globin 1 and alpha globin 2) (eg. Alpha thalassemia, Hb Bart hydrops fetalis syndrome, HBH disease) gene analysis for common deletions or variant (eg, Southeast Asian, Thai, Filipino, Mediterranean, alpha3.7, alpha4.2, alpha20.5, and Constant Spring) (if appropriate)
81401-HBB (hemoglobin, beta) (eg, sickle cell anemia, hemoglobin C, hemoglobin E), common variants (eg, HbS, HbC, HbE) (if appropriate)
81403-HBB (hemoglobin, beta, beta-globin) (eg, beta thalassemia), duplication/deletion analysis (if appropriate)
81404-HBB (hemoglobin, beta, Beta-Globin) (eg, thalassemia), full gene sequence (if appropriate)Hemoglobin S, Screen, Blood
85660 (if appropriate)
Hemoglobin F, Red Cell Distribution, Blood
88184 (if appropriate)
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 8268 | Methemoglobin, B | 2614-6 |
| 9322 | Methemoglobin Reductase, B | 32703-1 |
| 8272 | Sulfhemoglobin, B | 4685-4 |
| 2381 | Hemoglobin A2 | 4551-8 |
| 2380 | Hemoglobin A | 20572-4 |
| 586 | Methemoglobinemia Interpretation | In Process |
| 2383 | Variant | 32017-6 |
| 2382 | Hemoglobin F | 4576-5 |
| 29224 | Variant 2 | In Process |
| 29225 | Variant 3 | In Process |
| 2101 | Interpretation | 49316-3 |
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